The â€œForce themeâ€, also known as â€œBen Kenobiâ€™s themeâ€, â€œObi-Wanâ€™s themeâ€, or â€œMay the Force Be With Youâ€, is one of the most beloved of John Williamsâ€™ music for the Star Wars saga. It appears in all of the films, but perhaps most memorably in the Episode IV: A New Hope, when Luke contemplates his future while watching a pair of suns set on the horizon. [source]
Film Music Notes has a detailed breakdown of this theme (along with all of the other major musical themes in Star Wars), and it’s worth checking out if you want to learn more about the piece’s melody, rhythm, harmony, and orchestration. You can read it here.